BERKELEY, Calif. (UPI) — U.S. and Chinese scientists say they’ve found a hormone called insulin-like growth factor directs nerve connection formation in an area of the brain.

IGF had formerly been known only to stimulate the growth of cells throughout the body but the new study showed it also plays a critical role in establishing connections in the brain’s olfactory bulbs — a pair of small structures that analyze signals from about 1,000 different types of odor receptors in the nose.

University of California-Berkeley Professor John Ngai, the study’s principal author, said he and his colleagues believe IGF could become important when clinicians implant stem cells into organs to cure neurodegenerative diseases.

“Even if you figure out a way to grow new cells to replace dying cells, those cells still need to make proper connections,” Ngai said. “So, anything you know about what drives normal connectivity in the brain will help you figure out how to get those new cells to wire up correctly.”

Ngai and colleagues at the Shanghai Institutes of Biological Sciences and Columbia University reported their findings in the March 27 issue of the journal Neuron.